Buy 2003 Audi A4 3.0L V6 A/T Quattro Base Sedan Air Bag Impact Sensor (Rear). A4; Rear. A6/S6. Allroad - OEM Audi Part # 8E0959643E (8E0-959-643-E, 8E0959643A)

Sensor. Impact.
A Sensor to determine the location on the vehicle of Impact and the severity of the Impact to determine if and which air bags should be deployed. For. Air Bag. Ft. Side.

Air Bag Impact Sensor

Fits A4, A6, allroad, S4, S6

A4; Rear. A6/S6. Allroad; "C" Pillar. Rear seat. S4, RS4; Rear. SIDE AIR BAG, rear. SIDE AIR BAG, w/head air bag.
Air Bag Crash Sensor - Repair or Replace
An airbag or SRS light can sometimes indicate a problem with the impact sensor on your 2003 Audi A4, particularly if it's been involved in a collision—at any speed. Have a technician inspect your vehicle's crash sensor.